Why are my gums receding so quickly? (Photo)

You have a long way to go before you lose those teeth due to recession. It looks like the tissue graft did take and is still there. The increased forces on those teeth due to grinding is most likely causing your issue. You need a mouth guard to protect your teeth from the grinding forces. If you're grinding due to sleep apnea, you would need a sleep appliance. 

Hi Peaches,
Yes, i can see how the gum about your lower incisor teeth have started to recede a little...the good nes is, it doesn't appear too bad and if you can stop it getting worse, i dont think the teeth have been compromised long term (an xray of the teeth would certainly be useful to confirm this).
Gum recession most occurs due to 2 things, 1. Gum disease (periodontal disease) 2. incorrect brushing technique with a brush whose bristles are too hard.
The other causes of gum recession can be 3. parafunction - clenching & grinding of teeth can contribute to gum recession and 4. the position of the teeth within the jaw bone 5. presence of frenums and muscle attachments nearby.
Mt advise is to see a registered dentist to help identify the real cause of what is going on, however this advise is good for everyone - use extrasoft or  soft bristled toothbrushes, there is absolutely no need for anything harder and see a dentist / hygienist for regular teeth cleaning and prevention of gum disease.